What is the test for “voluntary assumption of risk” in the context of a claim for negligence?

The respondents take the position that the appellants were aware of the flammability of Thermaclad and this knowledge either relieves them of the duty to warn or discharges the duty. In Linden, Canadian Tort Law (5d) at 457, the author advises against the subsumption of voluntary assumption of risk within the duty issue. Rather, he argues, it should be treated as a defence. This approach has much to recommend it and it is the one I would adopt. I would also apply a narrow view of “volenti”. As Mr. Justice Estey stated in Dubé v. Labar, 1986 CanLII 67 (SCC), [1986] 1 S.C.R. 649; 68 N.R. 91; 1 Y.R. 81, at 658 [S.C.R.]: “Thus, ‘volenti’ will arise only where the circumstances are such that it is clear that the plaintiff, knowing of the virtually certain risk of harm, in essence bargained away his right to sue for injuries incurred as a result of any negligence on the defendant’s part. The acceptance of risk may be express or may arise by necessary implication from the conduct of the parties, but it will arise, in cases such as the present, only where there can truly be said to be an understanding on the part of both parties that the defendant assumed no responsibility to take due care for the safety of the plaintiff, and that the plaintiff did not expect him to. “Common sense dictates that only rarely will a plaintiff genuinely consent to accept the risk of the defendant’s negligence.”